I've placed my collection of useful stuff onto a Google drive folder too. Like @Wannabe_Maker, most of these I do not own the rights to, so use at your own risk for whatever purpose. There are two folders. @Wannabe_Maker, if you want to add these to your repository, that's fine with me.
This one is exclusively vector material:
At the moment, has a nearly complete set of F1 track maps, and a library of digital joints (dxf and iges)
This one has all of that, plus a number of raster images that would make easy conversions to vector. Has some grates, a lot of "ornamentation" vector/raster images that would be good sources of stuff, a bunch of frames, and a number of aircraft company logos (American Aviation, De-havilland, Vultee, Focke Wulf, Vultee, Messerchmit, Tupolev)